As for justifying this by arguing that a body which is a “person” and has volume must be one, so that applying the term “person” to oneness amounts to applying the name of one of two mutually entailing things to the other—this is false on several grounds.
First, a “person” that has volume is not one according to them, but composite, since every body is composite. The author of this foundational work stated at the beginning of this book: “His saying ‘One’ indicates the negation of corporeality, for a body is composed of at least two substances, and this is incompatible with oneness. The word ‘One’ expresses oneness emphatically; hence His saying ‘One’ is incompatible with corporeality.”
This point has already been discussed more than once. If, then, being a “person” and having volume entail the negation of oneness according to them, how can it be correct